find / -name 'string' -type f -print
/ - Directory to search. Can be replaced with "." to indicate just the current directory and it's subdirectories.
'string' - Filename containing this string. Wildcards are allowed
f - A type F indicates that you are only looking for files, as opposed to D for directories.
-print - Print result to the string, most versions of
find usually default this, so this is MOST probably not required. But it's a habit..
Regards